Field of the Invention
The present invention relates to a piezoelectric thin film and a method for manufacturing the piezoelectric thin film, and a piezoelectric element comprising the above piezoelectric thin film and first and second electrodes.
Description of the Related Art
Conventionally, a piezoelectric thin film comprising aluminum nitride containing scandium has been known to exhibit a high piezoelectric constant. On the other hand, scandium has been very expensive and has also been difficult to stably obtain. Therefore, aluminum nitride containing an element other than scandium has been widely researched.
For example, the following Patent Literature 1 discloses a piezoelectric thin film comprising an aluminum nitride film containing a divalent element and a tetravalent element, or an aluminum nitride film containing a divalent element and a pentavalent element. Patent Literature 1 shows the simulation results of the piezoelectric constant and the like of a piezoelectric thin film containing 14 aluminum atoms, 1 divalent element, 1 tetravalent element, and 16 nitrogen atoms.
Patent Literature 1: Japanese Patent Laid-Open No. 2013-219743
However, in the simulation in Patent Literature 1, it is assumed that an ideal atomic model can be formed, and therefore, the results are often not as simulated. Actually, problems relating to the solubility limits of the atoms, structural stability and the like occur. In addition, Patent Literature 1 only shows the simulation results for the particular composition as described above. Therefore, a composition that exhibits a higher piezoelectric constant and can be subjected to practical use cannot be known from the simulation results in Patent Literature 1.